Prediction of critical cutting depth for ductile-brittle transition in ultrasonic vibration assisted grinding of optical glasses

2016 ◽  
Vol 86 (5-8) ◽  
pp. 1775-1784 ◽  
Author(s):  
Ming Zhou ◽  
Peiyi Zhao
Keyword(s):  
Ultrasonic Vibration ◽  
Cutting Depth ◽  
Optical Glasses ◽  
Brittle Transition ◽  
Critical Cutting Depth ◽  
Ultrasonic Vibration Assisted Grinding

Chip Topography for Ductile-Regime Machining of Germanium

1994 ◽  
Vol 116 (2) ◽  
pp. 263-266 ◽  
Author(s):  
W. S. Blackley ◽  
R. O. Scattergood
Keyword(s):  
Diamond Turning ◽  
Cutting Depth ◽  
Machined Surface ◽  
Free Surfaces ◽  
Brittle Transition ◽  
Critical Cutting Depth ◽  
Independent Estimate ◽  
Ductile Regime Machining ◽  
Ductile To Brittle Transition ◽  
Insight Into

Ductile-regime response during the diamond turning of brittle germanium crystals is evident from the damage-free surfaces obtained. The nature of the ductile-regime processes cannot be determined by examination of the final machined surface itself. Machining chips were characterized using scanning electron microscopy. The chip topography provides insight into the ductile-to-brittle transition that occurs along the tool nose. A detailed examinaiton of the chips provides an independent estimate of the critical cutting depth for the transition.

scholarly journals Crack Forms Sensitivity-Based Prediction on Subsurface Cracks Depth in Ultrasonic-Vibration-Assisted Grinding of Optical Glasses

2021 ◽  
Vol 11 (16) ◽  
pp. 7553
Author(s):  
Peiyi Zhao ◽  
Lei Zhang ◽  
Xianli Liu
Keyword(s):  
Ultrasonic Vibration ◽  
Least Square ◽  
Effective Control ◽  
Support Vector ◽  
Prediction Errors ◽  
Optical Glasses ◽  
Subsurface Cracks ◽  
Proposed Model ◽  
Grey Relational ◽  
Ultrasonic Vibration Assisted Grinding

Subsurface cracks in ultrasonic-vibration-assisted grinding (UVAG) of optical glasses often exhibit diverse forms and proportions. Due to the variety of loads involved in crack formation and propagation, the crack forms and propagation depths have different sensitivities to each process parameter. Predicting the maximum subsurface cracks depth (MSSCD) by considering the varying effects of process parameters plays a key role in implementing effective control of the UVAG process. In this work, the subsurface crack forms and their proportions are investigated by conducting 40 sets of UVAG experiments. The varying effects of the grinding and ultrasonic parameters on the crack form proportions are unveiled by using grey relational analysis. The weighted least square support vector machine (WLS-SVM) prediction model for the MSSCD was developed. Twelve sets of UVAG experiments were carried out to validate the proposed model. The results show that arc-shaped cracks and bifurcated cracks account for 72.5% of all cracks, while ultrasonic vibration amplitude influences most of the proportions of arc-shaped and bifurcated cracks. Compared to other widely used prediction methods, the maximum and average relative prediction errors of the proposed model are 10.54% and 5.59%, respectively, which proves the high prediction accuracy of the model.

Study on the Cutting Deforming Force of Single Abrasive Grit for Ultrasonic Vibration Assisted Grinding along Normal Direction

2010 ◽  
Vol 102-104 ◽  
pp. 615-619 ◽  
Author(s):  
Hong Li Zhang ◽  
Jian Hua Zhang
Keyword(s):  
Cutting Force ◽  
Ultrasonic Vibration ◽  
Brittle Material ◽  
Grinding Force ◽  
Normal Direction ◽  
Kinematics Analysis ◽  
Cutting Depth ◽  
Force Ratio ◽  
Conventional Grinding ◽  
Ultrasonic Vibration Assisted Grinding

Based on the kinematics analysis and the cutting depth calculation of single abrasive grit, the mathematics models of the cutting deforming force and the average cutting deforming force were made by introducing the unit grinding force, Fu. And the formula of the average cutting force during the grinding zone was calculated. The experiments on the grinding force ratio were conducted under conventional grinding(CG) mode and normal ultrasonic vibration assisted grinding(NUAG) mode. The results showed that the unit grinding force in NUAG was lower than that in CG under the same machining condition; the grinding force ration was decreased due to the normal ultrasonic vibration of the workpiece. And it was helpful to improve the machinablity of the hard-brittle material.

Ultrasonic Vibration Assisted Grinding of Sintered Dental Zirconia Ceramics: An Experimental Study on Surface Roughness

2014 ◽  
Vol 1017 ◽  
pp. 800-805 ◽  
Author(s):  
Song Dong ◽  
Kan Zheng ◽  
Xing Zhi Xiao
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
Spindle Speed ◽  
Machining Process ◽  
Zirconia Ceramics ◽  
Cutting Depth ◽  
Hard And Brittle Materials ◽  
Input Variables ◽  
Dental Zirconia Ceramics ◽  
Ultrasonic Vibration Assisted Grinding

Dental zirconia ceramics have been widely used in dental restorations due to their superior aesthetical and mechanical properties. Ultrasonic vibration assisted grinding (UVAG), as a novel effective machining process for hard and brittle materials, is introduced into directly machining sintered dental zirconia ceramics. This study is dedicated to investigating the influence of input variables (spindle speed, feedrate and cutting depth) on surface roughness during UVAG of sintered dental zirconia ceramics. The experiment is conducted through single-factor method, and the experimental results are statistically analyzed by One-Way ANOVA. Besides, the influence tendency of input variables on surface roughness is also obtained. The results indicate that the influence of spindle speed on surface roughness is highly significant. The value of surface roughness rises with the increase of spindle speed, feedrate, and cutting depth. Therefore, a better surface quality will be achieved with the combination of lower spindle speed, cutting depth and feedrate.

Study on Grinding Force in Two-Dimensional Ultrasonic Grinding Nano-Ceramics

2010 ◽  
Vol 42 ◽  
pp. 204-208 ◽  
Author(s):  
Xiang Dong Li ◽  
Quan Cai Wang
Keyword(s):  
Mathematical Model ◽  
Ultrasonic Vibration ◽  
Contact Time ◽  
Reaction Force ◽  
Grinding Force ◽  
Two Dimensional ◽  
Indentation Fracture ◽  
Ultrasonic Grinding ◽  
The Impact ◽  
Ultrasonic Vibration Assisted Grinding

In this paper, the characteristic of grinding force in two-dimensional ultrasonic vibration assisted grinding nano-ceramic was studied by experiment based on indentation fracture mechanics, and mathematical model of grinding force was established. The study shows that grinding force mainly result from the impact of the grains on the workpiece in ultrasonic grinding, and the pulse power is much larger than normal grinding force. The ultrasonic vibration frequency is so high and the contact time of grains with the workpiece is so short that the pulse force will be balanced by reaction force from workpiece. In grinding workpiece was loaded by the periodical stress field, which accelerates the fatigue fracture.

Generation mechanism modeling of surface topography in tangential ultrasonic vibration-assisted grinding with green silicon carbide abrasive wheel

2021 ◽  
pp. 095440542110406
Author(s):  
Yutong Qiu ◽  
Jingfei Yin ◽  
Yang Cao ◽  
Wenfeng Ding
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Ultrasonic Vibration ◽  
Generation Mechanism ◽  
Surface Generation ◽  
Depth Of Cut ◽  
Abrasive Wheel ◽  
Grinding Parameters ◽  
Conventional Grinding ◽  
Ultrasonic Vibration Assisted Grinding

Tangential ultrasonic vibration-assisted grinding (TUAG) has a wide prospect in machining difficult-to-machine materials. However, the surface generation mechanism in TUAG is not fully recovered. This study proposes an analytical model of the surface topography produced by TUAG. Based on the model, the surface topography and roughness are predicted and experimentally verified. In addition, the influence of the grinding parameters on the surface topography is analyzed. The predicted surface topography well coincides with experimental measurements, and the prediction error in surface roughness Ra by the proposed model is less than 5%. Compared with conventional grinding, TUAG produces a surface with more uniform scratches and surface roughness Ra was reduced by up to 27% with the proper parameters. However, the improvement of surface roughness in TUAG is weakened when grinding speed or depth of cut increases. Moreover, the influence of the ultrasonic vibration amplitude on the surface roughness is not monotonous. With the grinding parameters selected in this study, TUAG with an ultrasonic amplitude of 7.5 μm produces the minimum surface roughness.

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